1. Field of the Invention
The present invention relates to a single-phase motor with a conversion circuit. In particular, the present invention relates to the use of a driver integrated circuit (model no. [US79KUA]), which is generally used with a two-phase motor, with a single-phase motor by means of connecting the driver integrated circuit with an external conversion circuit before connection to the single-phase motor. The output of the driver integrated circuit drives the single-phase motor under the control of the conversion circuit.
2. Description of the Related Art
A typical driver integrated circuit of model no. [US79KUA] includes three functional modules and three terminals. As illustrated in FIG. 1, the [US79KUA] single-phase motor driver integrated circuit (IC) includes a DC voltage-regulating circuit module, a control and protection circuit module, and a Hall latch module. The DC voltage-regulating circuit module supplies stabilized DC voltage to the control and protection circuit module and the Hall latch module, respectively, thereby providing a stable operational condition for the driver IC. The control and protection circuit module includes an auto-restart circuit, a locked rotor shutdown circuit, a reverse voltage protection circuit, and a Zener diodes protect outputs circuit. The Hall latch module includes a Hall element, a Hall voltage amplifier, and a motor driver. The Hall element detects a change in the magnetic field during rotation of the rotor, and the detected weak voltage is amplified by the Hall voltage amplifier and then outputted to drive the motor driver connected to the outputs (OUT1 and OUT2). Thus, a change in the current providing an alternate on/off function is generated in the Hall latch module. The stator of the motor is thus inducted to thereby turn the rotor, and the rotor turns continuously.
FIG. 2 depicts an application circuitry of the conventional [US79KUA] driver integrated circuit and a two-phase motor. FIG. 3 is a diagram illustrating output waves of the conventional [US79KUA] driver integrated circuit, wherein the abscissa denotes time and the ordinate denotes voltage. Referring to FIG. 2, a DC voltage (3-18V) of a power-supply is inputted via Vcc to power the driver IC. In this case, the Hall element of the driver IC detects a specific period of a change in a magnetic field generated by the permanent magnet of the rotor. When the terminal OUT 1 is close, the current passes the Coil 1 to drive the rotor through a certain angle. Due to the change in the angular position of the rotor, the Hall element detects another period of the change in the magnetic field generated by the permanent magnet. At this time, the terminal OUT 1 is open and the terminal OUT2 is close such that the current passes the Coil 2 to drive the rotor through another certain angle. Referring to FIG. 3, the terminals OUT1 and OUT2 are alternately opened and closed in a synchronous manner to output square waves of identical frequency and inverted phases. Thus, the rotor is continuously driven by inducted repulsive forces generated by the Coil 1 and Coil 2 in alternative phases. However, such a driver IC can only be used with a two-phase motor having two coils; namely, it cannot be used with a single-phase motor having a single coil.
The primary object of the present invention is to provide a single-phase motor having a conversion circuit, wherein a [US79KUA] two-phase motor driver IC is connected to a single-phase motor via an external conversion circuit. The conversion circuit receives the output signals of the [US79KUA] driver IC to control alternate on/off of two transistors serially connected to two ends of a coil for a motor. The [US79KUA] two-phase motor driver IC can be selected to apply in a single-phase motor.
The secondary object of the present invention is to provide a single-phase motor having a conversion circuit, wherein the [US79KUA] two-phase motor driver IC can be used with a single-phase motor having a single coil and a simple structure. The coil structure is thus simplified, and the motor quality is improved.
A further object of the present invention is to provide a single-phase motor having a conversion circuit, wherein the [US79KUA] two-phase motor driver IC is connected to a single-phase motor via an external conversion circuit. The conversion circuit further comprises two sets of voltage-dividing circuits for reducing the power voltage to a proper extent. Thus, the available voltage of the motor is not limited by voltage feature of the [US79KUA] two-phase driver IC. As a result, the motor may work in a wider input voltage range.
The single-phase motor having a conversion circuit in accordance with the present invention comprises a [US79KUA] two-phase motor driver IC, a conversion circuit, and a coil for a motor. The driver IC includes two outputs that are serially connected to the conversion circuit and then connected to the coil. The conversion circuit includes two transistors respectively connected two ends of the coil. The outputs of the driver IC respectively send out alternate on/off signals to respectively turn the transistors on and off, thereby controlling directions of current passing the coil. Thus, the coil generates alternative magnetic fields as a result of alternative directions of the current to thereby drive the rotor. In addition, the conversion circuit comprises two sets of voltage-dividing circuits for reducing the power voltage to a proper extent such that the motor may work in a wider input voltage range. Thus, the available voltage of the motor is widened and not limited by voltage feature of the driver IC.
Other objects, specific advantages, and novel features of the invention will become more apparent from the following detailed description and preferable embodiments when taken in conjunction with the accompanying drawings.